Elastic yarn feeding means for



Feb. 10, 1953 R. H. LAWSON 2,627,738

ELASTIC YARN FEEDING MEANS FOR KNITTING MACHINES Filed Jan. 12, 1951 3 Sheets-Sheet l INVENTOR ROBERT H. LAWSON ATTORNEYS 3 Sheets-Sheet 2 R. H. LAWSON Feb. 10, 1953 ELASTIC YARN FEEDING MEANS FOR KNITTING MACHINES Filed Jan. 12, 1951 INVENTOR ATTORNE A. R'BERT H. LAWSON Feb. 10, 1953 R, H. LAWSON 2,627,738

ELASTIC YARN FEEDING MEANS FOR KNITTING MACHINES Filed Jan. 12, 1951 3 Sheets-Sheet 5 INVENTOR ROBERT H. LAWSON BY Z I I r I ATTORNEV-YZ Patented Feb. 10, 1953 ELASTIC YARN FEEDING MEANS FOR KNITTING MACHINES Robert H. Lawson, Laconia, N. H., assignor to Scott & Williams, Incorporated, Laconia, N. H., a corporation of Massachusetts Application January 12, 1951, Serial No. 205,744

9 Claims.

1 This invention relates to elastic yarn feeding means for knitting machines. It has particular reference to the proper feeding of elastic strands and, particularly, bare rubber to knitting machines for the making of girdle or similar elastic fabrics.

In the feeding of bare rubber to knitting machines either to be laid into the fabric or to be knit therein it is very important to maintain the proper extension since the thin bare rubber yarns are readily extended by even a slight amount of tension.

Itis particularly necessary to provide accurate control when a plurality of such yarns are simultaneously fed to different feeds of a multiple feed machine. Under such conditions, it is usually desired to produce precisely the same results at various feeds. For example, in a machine having a total of six feeds, the repeat of the knitting pattern may be three feeds. As a consequence, the first and fourth feeds of such a machine should produce precisely the same stitches. If that end is properly accomplished, a fabric of desired appearance may result; but on the other hand, if that end is not accomplished, the fabric may have a horizontally ribbed appearance which is objectionable.

Non-uniformity of feed of several elastic strands may be due to various causes. Not only may the non-uniformity result from improper control of the strands where the primary control is supposedly effected, but between that control and the needles there may be differences in the retardation of the yarn due for example, to differences in path from the standpoint not only of the elements through which the yarn is guided in the path but the length of the path as well. The effect of the latter, for example, is due to the difference in the length of the strand or yarn through which it may absorb irregularities. In brief, irregularities may appear locally applied to the strands at the point of major control. If the yarn was immediately knitted, these irregularities would appear in the fabric. However, if a substantial distance is involved in the path of the elastic yarn between the controlling devices and the point of knitting, the irregularities tend to even out due to the elasticity of the yarn. Obviously, if the two elastic yarns follow different paths, such evening out of irregularities will take place to different degrees resulting in nonsimilarity of the stitches which are produced.

In accordance with the present invention not only are the individual rubber strands or yarns properly controlled, but rubber strands supposed to be laid in or knit identically are properly controlled so as to give rise to a high degree of achievement of that result.

.The invention alsoprovides for the feeding of a plurality of yarnsin proper related fashions even though the several yarns are supposed'to be knit or laid in in different fashions, for example one of the yarns may consist of rubber of one size and the other of rubber of a different size which should be fed to knit at different rates.

The invention alsoprovides for the control of the rate of feed variably during the knitting of a garment, for example, for the purpose of shaping the same.

Provisions are also made in accordance with the invention for the proper lubrication of elastic yarns such as those of bare rubber.

Provision is also made in accordance. with the invention for the proper application of a stop motion to stop the knitting machine upon breakage of any of the elastic yarns.

The general objects of the invention relate to the attainment ofthe results above indicated. These and other objects of the invention particularly relating to details of construction .and operation will become apparent from the'following description read in conjunctionwith the accompanying drawings, in which:

Figure 1 is an elevation showing certain parts of a circular knitting machine with the invention applied thereto;

Figure 2 is a plan view, partly in section, of the parts shown in'Figure 1;

Figure 3 is an elevation looking at the left "of Figure 1;

Figure 4 is a vertical sectionthrough the .axis of the pair of yarn feeding capstans shown in the foregoing figures;

Figure '5 is a horizontal section through'the axis of a pair of variable sheaves provided for speed adjustment; and

Figure 6 is a vertical section showing the driving arrangement for the capstan-screws.

While the invention is applicable toother machines, such as V-bed'machines, it is illustrated as applied to a multi-feed circular'knitting'machine 2 which is only diagrammatically indicated in the drawings. It may 'be assumedthat the machine is knitting shaped girdleor similar-fabrics and the elastic yarns which will'be referred to may be assumed to be bare natural or artificial rubber, though itwill be evident that the invention is in some respects applicable to the knitting orother incorporation into an elastic fabric of covered rubber.

"The positions of certain of :the multiple feeds of the knitting machine are'illustrated generally at 4. As will be evident, the rubber strands 5 which are fed'to the machine may be laid in the fabric, knit in, or interlaced,'the invention being applicable to any one of these modes of incorporation of rubber or to combinations thereof.

In each case, control of extension of rubber strands is of importance, and if in thesame fabric some rubber strands are knit in while others are laid in it is important not only to control the individual extensions but the relative extensions of the strands as well. As will become clear hereafter this is properly eifected in accordance with the invention.

There is indicated at 6 a shaft which may be either an extension of the main driv shaft of the knitting machine or may be a shaft connected thereto by gearing. This shaft 6 carries a sprocket 8 which serves through a chain I to drive the mechanism which embodies the present invention. The chain It is trained over a driven sprocket I2 which carries a bevel gear I4 meshing with a second bevel gear I8 splined to a shaft I8 which is horizontally displaceable. The bevel gear I6 is held in axial position against one arm 24 of a bracket by means of a sleeve 2!! surrounding shaft I8 and engageable with the other arm 22 of the same bracket, the shaft I8 being mounted in these arms. At 26 and 28 there are indicated drive sheaves of the expanding or Reeves type. The right-hand element 30 of sheave 28 is mounted on the shaft I8 for free axial movement relative thereto and is prevented from moving toward the right by the bracket extension 32 through which the right-hand end of shaft I8 projects. The right-hand element 34 of sheave 26 bears against the bracket arm 22 which prevents right-hand movement thereof, this element also being mounted for free axial movement relative to shaft I8. The left-hand element 36 of sheave 28 is secured to the shaft I8 7 by means of a set screw 38. and the left-hand ele ment 40 of sheave 26 is similarly secured to shaft I8 by means of the set screw 42.

The shaft I8 is constantly urged toward the left by the tension of the elastic belts which are driven by the sheaves 26 and 28 and which tend to force apart the elements of both sheaves. The movement of the shaft I8 to the right is controlled by the action of a bell crank 44 which is pivoted at 45 to a bracket 41 carried by the frame of the machine. The lower horizontal arm of the lever 44 has a pad on which bears an adjustable screw 46 carried by an extension 48 of a lever 50 provided with a cam follower 52 arranged to be acted upon during operation of the machine by one or more cams 54 on the conventional main cam drum 56 of the machine. The upwardly extending arm of the bell crank 44 is adapted to engage an adjustable screw 60 carried by an extension 58 of bracket 4'! whenever the follower 52 is released by cams on the main cam drum. An adjustable screw 62 is carried by the upwardly extending arm of bell crank 44 and is arranged to bear against a hardened plate 63 secured to element 40 of sheave 26.

. A considerable degree of both manual and automatic adjustment of the diameters of the sheaves is efiected by the arrangements described. The left-hand elements of th sheaves may be locked in various relative adjusted positions by the set screws 38 and 42. Adjustment of screw 62 sets the relative position of the shaft I8 with respect to the bell crank 44 and hence simultaneously adjusts the maximum and minimum diameters of the sheaves. The minimum effective diameters are also separately set by adjustment of the abutment screw 60, while the maximum diameters are set by the adjustment of the screw 46 through which movements are imparted from the cam or cams 54 which may have gradual as well as abrupt rises and falls for contouring of the products. It will be evident from these adjustments that there is not only a wide range of relative adjustment but simultaneous adjustments of both sheaves to corresponding extents may be effected automatically during operation by cam action on the follower screw 46.

The sheaves 26 and 28 respectively drive rubber stretching units of the capstan type through elastic belts 64 and 68. A horizontal shaft 68 is journalled in the bracket members 70 and I2 to which are secured gears I4 and I6. Meshing with the fixed gear I4 which is concentric with the shaft 68, are the pinions I8 carried by spindles 88 journalled in a sheave 82 which is secured to the shaft 68 by the key 84 and set screw 86. There are provided a plurality of spindles 80, preferably at least three, and in the present case these are illustrated as four in number. The spindles 88 are extended toward the left as viewed in Figure 4 in the form of right-hand screws 88. These screws may have various forms of threads but V-threads have been found highly satisfactory.

In similar fashion there mesh with th fixed gear I6 the pinions 90 carried by spindles 92 which are journalled in a sheave 84, the spindles 95 being extended toward the right in the form of left-hand screws 96. The parts just described are held in assembled relationship by the provisions of a collar 98 secured to the shaft 68. The shaft 68 has a small diameter extension I00 at its right-hand end for driving purposes as hereafter described.

The rubber strands which are involved in the operation of the machine are led upwardly from supplies which may be in the form of cones from which the strands may be unwound with little initial tension. The rubber strands pass upwardly through eyes I82 and are wound about the screws of the capstans as indicated most clearly in Figures 1 and 2. These rubber strands 5 then pass over lubricating rolls I04 and I06 which are adapted to dip into lubricating liquid in tanks I08 which may be connected to inverted bottletype supply devices I09 of conventional type which serve to maintain substantially uniform level of liquid within the tanks. The rolls I04 and I88 are carried by a shaft III! which at its right-hand end as viewed in Figure 3 carries a large diameter pulley II2 which is driven from the spindle extension I00 by means of an elastic belt I I4 which may conveniently be no more than a rubber band. The arrangement is such that the rolls have imparted to them a low rate of rotation as compared with the linear velocity of the rubber strands, the direction of rotation being counterclockwise as viewed in Figure 1 so that their surfaces move in retrograde direction with respect to the rubber strands passing thereover.

From the lubricating roll I06 the strands at the right-hand side of the machine as viewed in Figure 2 pass to pulleys H6 carried for free rotation by a fixed spindle II8 supported by a bracket I28 from a fixed portion of the machine frame. From the pulleys II6 the rubber strands pass to pulleys such as I22 and I24 which are mounted for free rotation on spindles which are carried in a fashion providing universal adjustment by devices such as indicated at I26 and I28 which are supported by fixed portions of the machine. At the left-hand side the strands leaving roll I 04 are directed by elements similar to those just described and designated by the same reference numerals primed.

Stop motion devices I38 of conventional electrical type are provided with arms I32 which have speeds remains fixed.

asst-yea hooked ends lt l held up by the-rubberstrands between the capstans andthe-lubricating rolls.

These stop motion devices are individual to the several strands and are connected to stop the knitting machine 'in the event that any of the "arms I32 drops in view of breakage of a rubber the rubber strands without any damage thereto such as may occur if feed rolls squeezing the rubber are used. Very little slippage occurs between the rubber strands and the capstan screws and this slippage is reduced to a "negligible amount through the Winding of the strands several times about the capstans. In the case of bare rubber three of four turns about the screws will sufiice; with covered rubber six'or more turns "are desirable.

the rubber strand on the capstan, the resulting helix remaining in substantially constant position throughout the operation after once having attained the stable position. The last mentioned situation makes it possible to feed a number of elastic strands from the same capstan, and inasmuch as all such strands are identically handled the amount of stretch is constant so long as the ratio of capstan and knitting machine It follows that, subject toproper handling beyond the capstan, a plurality of strands 5 such as the two illustrated in Figure 1 may be fed identically to the knitting elements. To insure uniformity of handling, the

strands are similarly passed over a lubricating roll such as 186 whereby lubricantis applied, this roll having a speed which for a particular adjustment remains constant with respect to that of the capstan. The frictional drag imposed by the lubricating roll is quite small. All strands of a similar type of rubber should have the same number of turns about a capstan to insure uniform extension.

The described capstan type of feed has a further pronounced advantage over the squeeze roll type of feed. If the-cone from which the rubber is being drawn has arough top, the strand at times may catch and hold back. When thishap- ,pens during feeding by squeeze rolls, the strand will usually pull loose but the extra extension of the rubber carries through to the fabric and tighterstitches are locally drawn as a result.

When the same thing happens while feeding with a corrugatedsheave about which the rubber is normally given one and a half turns, the strand holds back until the tension is sufiicient to pull it free and then it snaps ahead on the sheave so that itis fed to the needles with less than the required amount of stretch and causes loose stitches.

When, however, the rubber fed by the present capstan type of feeder catches on the cone, neither noticeably tighter nor looser stitches result, probably due to the several turns of the strand about the screws'which absorb the variations between the point of approach of the strand --to the capstan-and the point of delivery of the strand from the capstan.

secure unifc'rmitycf control (if a id" What is particular-1y unpcrtant, 'wever, "to H lity o'f strands, is that the 'strandsshould ha Inform paths between the "capstan and the'poi'ntswhere they are engaged in the 'fabric being knitted. First,-it is important that they should feed over, and be guided by, the same number 'of freely rotatable pulleys. Aswill be evident from Figure 1 this end is essentially achieved. The-fact that the strand in one cas'e 'inayturn about agreater angle of contact with a pulley than in another case does not substantially affect theunifcrmity of conditions provided that the pulleysare freely rotatable. Additionally, however, the-total length of path should be substantially uniform. Rubber strands as commercially provided are not uniform in diameter or cross-'section andconsequently are not uniform in extensibility. It follows that fluctuations of tension occur jas the rubber strand passes between the capstan feeder and the needles of the machine. If an elongated path is provided 'theirreg ularitie's tend to cancel out in their efiects and thiscan'cellation depends to some extent on the lengths of the paths. To insure a uniformity of this action it is desirable that the paths should be of approximately the same length. Figures 1 and 2 indicate l'lOW this result may be achieved in particular by providing universally adjustable pulleys such as indicated at I22 and H4 whereby not only the lengths of the paths may bemade uniform but there may also be simultaneously controlled thedirection of approach of the strands to the needles. It-will be noted that the pulleys I [6 are located at approximately "the same distance from both final feeding pulleys E22 and 1'24, which are in turn equidistant from the points where the'strands meet the needle circle. Thus substantially the same path lengths for'thepair of strands aresecured.

In order "to provide shaping cf the knitted fabric the extension "of the strands should be changed during the knitting. This is effected by the controlfrom the cam or cam's '54 on the main cam drum of themachine which'change the rate of rotation of the capstans thereby contr'o1ling the extension of the'rubber strands at the time of approach to the-needles. The'provision of the adjustments'of the sheave elements, the'screw'62 and the stop screw '60 provide almost universal relative adjustments of the extension of the strands. The deviation from 'coinple'te universality is involved in the 'fa'ct'that both-'capstans feeding diiierent strands or groups of strands are simultaneously controlledas to speed by the cam or cams '54. "However, 'this'is not 'a practical drawback inasmuch as when one set-of rubber strands is to be extended it is practically universally necessary that the strands of "another set should be correspondingly extended. Hence there is noticed for provision for independent change of speed ratios 'for'the two capstans.

The elastic strands are properly lubricated after leaving the capstans. If lubricated threads were wound about the capstans some slippage might'occur resulting in non-uniformity of-"the extension.

The stop motions also desirably'p'recede the lubrication since in general, lubrication is 'effected by liquids'which would be deleterious "to electrical devices and if lubrication preceded the point of engagement of the s'tra'ndsby the stop motion feelers it would be difiicult to prevent the lubricating liquid from reaching the electrical elements.

It maybe noted that the stop motion devices will act immediately if breakage occurs beyond the capstans. If breakage occurs in advance of a capstan, however, the feed may properly be continued until the strand passes ofi the capstan whereupon the machine will be stopped. The same condition exists if the supply is exhausted.

As was previously noted, the described feeding means may be used for knitting in, laying in, or interlacing elastic yarns or for various combinations of these procedures simultaneously carried out. When knitting elastic yarns it is possible to arrange pulleys such as 122 and I24 to aiford tangential approach of the yarn to the needles without the necessity for provision of additional guiding means between the pulleys and the needles. On the other hand, as when laying in the yarn it may be desirable to provide a guiding tube or eye closely adjacent to the needles to attain proper precision of approach. If such a guide is of a smooth type to impose a minimum of friction on the yarn it will not deleteriously afiect the advantages of the invention.

What is claimed is:

1. In combination with knitting mechanism having a plurality of feed points, a feeding head of capstan type for receiving a plurality of elastic strands, said strands being wound about said head, and means for guiding said strands to the respective feed points, said means comprising an array of freely rotatable pulleys about which said strands pass and so arranged that each strand passes about the same number of pulleys between the feeding head and its corresponding feed point.

2. In combination with knitting mechanism having a plurality of feed points, a feeding head of capstan type for receiving a plurality of elastic strands, said strands being wound about said head, and means for guiding said strands to the respective feed points, said means comprising an array of freely rotatable pulleys about which said strands pass and so arranged that each strand has approximately the same length of path tic strands, said strands being wound about said head, and means for guiding said strands to the respective feed points, said means comprising an array of freely rotatable pulleys about which said strands pass andso, arranged that each strand passes about the same number of pulleys and has approximately the same length of path between the feeding head and its corresponding feed point. l g

4, In combination with knitting mechanism, a plurality of rotating feeding heads of capstan type for receiving elastic strands, said strands being wound about said heads, means for guiding said strands from said heads to the knitting mechanism, said guiding means providing free, substantially unretarded, advance of said strands between the heads and the knitting mechanism at .a rate substantially solely determined by the relative speeds of said heads and of operation of the knitting mechanism, and means for varying the relative feeding speeds of said heads with respect to each other.

5. In combination with knitting mechanism, a plurality of rotating feeding heads of capstan type for receiving elastic strands, said strands being wound about said heads, means for guiding said strands from said heads to the knitting mechanism, said guiding means providing free, substantially unretarded, advance of said strands between the heads and the knitting mechanism at a rate substantially solely determined by the relative speeds of said heads and of operation of the knitting mechanism, and means for varying the feeding speed of at least one of said heads with respect to the speed of operation of the knitting mechanism.

6. In combination with knitting mechanism, a plurality of rotating feeding heads of capstan type for receiving eleastic strands, said strands being wound about said heads, means for guiding said strands from said heads to the knitting mechanism, said guiding means providing free, substantially unretarded, advance of said strands between the heads and the knitting mechanism at a rate substantially solely determined by the relative speeds of said heads and of operation of the knitting mechanism, and means for simultaneously varying the feeding speeds of said heads with respect to the speed of operation of the knitting mechanism,

'7. In combination with knitting mechanism, a plurality of rotating feeding heads of capstan type for receiving elastic strands, said strands being wound about said heads, means for guiding said strands from said heads to the knitting mechanism, said guiding means providing free, substantially unretarded, advance of said strands between the heads and the knitting mechanism at a rate substantially solely determined by the relative speeds of said heads and of operation of the knitting mechanism, and means for varying the relative feeding speeds of said heads with respect to each other and for simultaneously varying the feeding speeds of said heads with respect to the speed of operation of the knitting mechanism.

8. In combination with knitting mechanism, a stretching device for an elastic strand, means for guiding said strand from the stretching device to the knitting mechanism, and means for applying lubricant to the strand, the last mentioned means comprising a roller, and means for driving said roller at a speed bearing a predetermined relationship to the speed of feed of the stretching device.

9. In combination with knitting mechanism, a stretching device for an elastic strand, means for guiding said strand from the stretching device to the knitting mechanism, and means for applying lubricant to the strand at a point between the stretching device and the knitting mechanism, the last mentioned means comprising a roller, and means for drivin the roller, said roller engaging said strand and rotating at the point of engagement with the strandin a direction opposite the advance of the strand.

ROBERT H. LAWSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

